Multiposition caster lock for airplane cross-wind main landing wheels



E. WOLF 2,656,995 MULTIPOSITION CASTER LOCK FOR AIRPLANE CROSS-WIND MAINLANDING WHEELS Filed May 9, 1951 Oct. 27, 1953 r ml... 2

IN V EN TOR. Edward h o/f holes 25 in the brake drum M after casteringof the wheel has taken place and hydraulic pres'-' sure is applied tothe cylinder It to hold the wheel fixed against castering. Ihe verticalpositions of the holes 25 are placed to correspond to the curvature ofcam 8. With the pressure off from pin 22 it is retractedfrom its hole sothat spring 19 becomes active again for damping f wheel shimmying. Twosprings are being used in this arrangement, one for disengaging the lockpin from the brake drum after fluid pressure is released from thecylinder, and the other to provide the necessary friction force todampen wheel shimmying. Although not giving the infinite adjustment ofthe friction lock described above, the effect is for practical purposesthe same.

Having described the invention, it will be understood that the objectsof the invention, to hold the landing wheels in a fixed casteredposition, have been achieved in a most simple and practical way.

While certain representative embodiments and details have been shown forthe purpose of illustrating the invention, it will be apparent to thoseskilled in the art that various changes and modifications may be madetherein without departing from the spirit or scope of the invention.

What I claim:

1. In an airplane cross-wind landing gear, a strut having at its bottoma wheel axle attached thereto, said axle being provided at its outer endwith a bore forming a caster brake cylinder, a king pin disposed at anangle with the horizontal and being axially slidable and pivotable insaid axle, a hollow wheel hub fixed to said pin and being radiallyspaced from said axle, a wheel rotatably mounted on said hub and beingfreely casterable about said pin, a cam within and being seated at thebottom of said hub, a pair ofcam followers fixed to the bottom of saidaxle in contact with said cam, a spring concentric with the king pin andseated on said axle for centering the wheel in the cam when in the air,a caster multi-position locking device including a brake drum segmentfixed to the wheel hub and being concentric to the king pin axis, ahydraulically, as well as spring actuated piston provided with afriction pad and movable within said brake cylinder for frictionalengagement with said brake drum segment, and a pressure fluid conduitconnected to said brake cylinder for applying pressure against thepiston to actuate the brake for arresting the eastered wheel positionsubstantially at the caster angle the wheel assumes when touchingground, however, said locking device with the hydraulic pressurereleased providing sufficient friction by spring action to dampenshimmying of the wheel.

2. In an airplane cross-wind landing gear, a

strut having at its bottom a wheel axle attached thereto, said axlebeing provided at its outer end with a bore forming a caster brakecylin-i der, a king pin disposed at an angle with the horizontal andbeing axially slidable and pivot-v able in said axle, a hollow wheel hubfixed to said pin and being radially spaced from said axle, :a wheelrotatably mounted on said hub and being freely casterable about saidpin, a cam within and being seated at the bottom of said hub, a pair ofcam followers fixed to the bottom of said axle in contact with said cam,a spring concentric with the king pin and seated on said axle forcentering the wheel in the cam when in the air, a caster multi-positionlocking device including a brake drum segment fixed to the wheel hub andbeing concentric to the king pin axis, a :piston slidably mounted in thebrake cylinder, a friction pad on the piston,

spring means behind the piston for normally holding the pad against thebrake drum segment to dampen wheel shimmying, and a con- .duit forsupplying fluid under pressure behind the piston to lock the wheelagainst castering.

3. In an airplane cross-wind landing gear, a strut having at its bottoma Wheel axle attached thereto, said axle being provided at its outer endwith a bore forming a caster brake cylinder, a king pin disposed at anangle with the horizontal and being axially slidable and pivotable insaid axle, a hollow wheel hub fixed to said pin and being radiallyspaced from said axle, a wheel rotatably mounted on said hub and beingfreely casterable about said pin, a cam within and being seated at thebottom of said hub, a pair of cam followers fixed to the bottom of saidaxle in contact with said cam, a spring concentric with the king pin andseated on said axle for centering the wheel in the cam when in the air,a caster multi-position locking device including a brake drum segmentfixed to the wheel hub and being concentric to the king pin axis, apiston slidably mounted in the brake cylinder, spring means behind thepiston for normally holding it against the brake drum segment to dampenwheel shimmying, and a conduit for supplying fluid under pressure behindthe piston to lock the Wheel hub against castering.

4. In an airplane cross-wind landing gear, a strut having at its bottoma wheel axle attached thereto, said axle being provided at its outer endwith a bore forming a brake cylinder, a king pin disposed at an anglewith the horizontal, a hollow wheel hub mounted on said pin and beingradially spaced from said axle, a wheel rotatably mounted on said huband being casterable about the king pin axis, a caster multipositionlocking device including a brake drum segment fixed to the wheel hub andbeing concentric to the king pin axis, a piston slidably mounted in thebrake cylinder, a friction pad on the piston, spring means behind thepiston for normally holding the pad against the brake drum segment todampen wheel shimmy, and a conduit for supplying fluid under pressurebehind the piston to lock the wheel hub against castering.

5. In an airplane cross-wind landing gear including a fixed wheel axle,a landing wheel hub casterably mounted to said axle, a hydraulicallyoperated caster brake disposed between said axle and said hub, saidbrake consisting of a cylinder formed within the outer end of said Wheelaxle a pressure fluid conduit leading to said cylinder, a piston in saidcylinder, a spring 'in back of the piston for forcing it outwardly, a

friction pad seated on the piston, :a pressure sealed flanged pinmovable in said piston and in said pad, a spring for keeping said pin inretracted position, a brake drum segment fas 5 tened to the casterablewheel hub and being provided with a plurality of registering holes forengaging said pin, when hydraulic pressure is applied to the cylinder inback of the piston, said pin being retracted from said drum when thehydraulic pressure is released from said cylinder.

EDWARD WOLF.

References Cited in the file of this patent UNITED STATES PATENTS NumberNumber Number 265,650 704,249

Name Date Wolf Nov. 22, 1949 Loudenslager Apr. 11, 1950 Smith Sept. 26,1950 Lucien Oct. 10, 1950 Burnelli May 22, 1951 Sievers July 17, 1951FOREIGN PATENTS Country Date Great Britain Feb. 9, 1927 France Feb. 17,1931

